BENGAL INSTITUTE OF TECHNOLOGY

MAKAUT CONTINUOUS ASSESSMENT 2 (CA2): Report Writing

Even Semester, 2024-25

Name: SARIF HOSSAIN MOLLA Roll No.:12100123123

Semester: 4th Stream:CSE

Paper Name: Biology Paper Code: BSC 401

Topic: The Function of RNA

Title: The Function of RNA

Introduction to RNA

• Introduction

o RNA (ribonucleic acid) is a vital molecule involved in several cellular

processes, including protein synthesis, regulation, and gene expression. It
plays a crucial role in translating the genetic code into functional
proteins, as well as in other activities such as RNA splicing and gene
silencing.

o Unlike DNA, which serves as the blueprint for life, RNA is a messenger
and catalyst in the cell, helping ensure that genetic instructions are
carried out.

Structure of RNA

• Chemical Composition

o RNA is composed of nucleotides, each containing a sugar

 o (ribose), a phosphate group, and a nitrogenous base (adenine

o [A], uracil [U], cytosine [C], and guanine [G]). This is similar to DNA,
but instead of thymine (T), RNA contains uracil (U).

o RNA is usually single-stranded, although certain types of RNA can form

secondary structures, like hairpins or loops, that give it a more complex
3D shape.

• Types of RNA

o mRNA (Messenger RNA):

Carries the genetic code from DNA to the ribosomes.

o tRNA (Transfer RNA):

Transfers amino acids to the ribosomes for protein synthesis.

o rRNA (Ribosomal RNA):

Forms part of the ribosome and helps catalyze the formation of peptide
bonds between amino acids.

o snRNA (Small Nuclear RNA):

Involved in splicing of precursor mRNA.

o miRNA (MicroRNA) and siRNA (Small Interfering RNA):

Play roles in gene silencing and post-transcriptional regulation.

RNA Transcription Process

• The Central Dogma of Molecular Biology

o The central dogma outlines the flow of genetic information: DNA →

RNA → Protein.
 • Transcription Mechanism

o Transcription is the first step of gene expression, where RNA is

synthesized from a DNA template. The process occurs in three stages:

▪ Initiation: RNA polymerase binds to the promoter region of a

gene.

▪ Elongation: RNA polymerase adds nucleotides to the growing

RNA strand, complementary to the DNA template.

▪ Termination: RNA polymerase reaches a termination signal,

causing the RNA strand to be released.

• Role of RNA in Transcription

o RNA polymerase is essential in catalyzing the synthesis of RNA from the

DNA template during transcription.

mRNA and Its Function in Protein Synthesis

• mRNA Structure and Function

o mRNA is the template used in protein synthesis. It is transcribed from the

DNA and carries the genetic code to the ribosomes for translation into
proteins.

• Process of mRNA Processing

o Before mRNA leaves the nucleus in eukaryotes, it undergoes

modifications:

▪ Capping: A 5' cap is added to the mRNA, protecting it from

degradation.

▪ Polyadenylation: A poly-A tail is added to the 3' end, aiding in

stability and export from the nucleus.

▪ Splicing: Introns are removed, and exons are joined together.

 • Translation of mRNA

o The mRNA is then translated by the ribosomes to form a protein. Codons

on the mRNA determine the sequence of amino acids in the protein.

tRNA and Protein Synthesis

• Role of tRNA in Translation

o tRNA molecules are responsible for bringing amino acids to the

ribosome in the correct sequence based on the mRNA codons. Each
tRNA has an anticodon that matches the codon on the mRNA, ensuring
accurate translation.

• Structure of tRNA

o tRNA has a characteristic cloverleaf shape with an anticodon loop at one

end and an amino acid attachment site at the other.

• Translation Process

o The ribosome reads the mRNA codons and recruits tRNA molecules that
bring the appropriate amino acids to the ribosome for the synthesis of the
polypeptide chain.

rRNA and Ribosomes

• Structure and Function of rRNA

o rRNA is a structural component of ribosomes, the molecular machines

responsible for protein synthesis.

o Ribosomes consist of two subunits, large and small, both of which

contain rRNA. The rRNA facilitates the binding of mRNA and tRNA
and catalyzes peptide bond formation between amino acids.

• The Role of rRNA in Translation

o rRNA also provides the catalytic site for the synthesis of protein chains
and ensures the correct alignment of mRNA and tRNA during
translation.
RNA Processing and Modifications

• RNA Splicing
o In eukaryotes, after mRNA is transcribed, it undergoes splicing, where
introns (non-coding regions) are removed and exons (coding regions) are
joined together.

o Spliceosome: A complex of snRNA and proteins that carries out this

process.

• RNA Editing

o In some cases, RNA molecules undergo editing, where specific

nucleotides are altered, inserted, or deleted, changing the resulting
protein's function.

• Other Modifications

o Methylation: Addition of methyl groups to RNA molecules that can

regulate gene expression.

o Adenylation: Addition of adenine residues to RNA, affecting stability

and degradation.

Non-Coding RNA and Gene Regulation

• miRNA and siRNA

o MicroRNA (miRNA) and small interfering RNA (siRNA) are involved

in regulating gene expression by binding to complementary mRNA
molecules, causing their degradation or preventing translation.

• RNA Interference

o RNA interference (RNAi) is a process where small RNA molecules

inhibit gene expression by interacting with mRNA and preventing
translation.

• Role of ncRNA in Gene Silencing

o Long non-coding RNAs (lncRNA) and other ncRNAs have diverse roles
in regulating chromatin structure and gene expression, often by
interacting with DNA or RNA.
RNA in Cellular Functions Beyond Protein Synthesis

• RNA as a Catalyst: Ribozymes

o Some RNA molecules function as enzymes, called ribozymes, capable of

catalyzing biochemical reactions. Ribozymes play roles in RNA splicing,
virus replication, and other cellular processes.

• RNA in Virus Replication

o Certain viruses, especially RNA viruses like HIV and influenza, use
RNA as their genetic material. These viruses rely on RNA-dependent
RNA polymerases to replicate their RNA genomes within host cells.

• RNA in the Immune System

o RNA is involved in various immune responses, such as activating

antiviral defenses. For example, the recognition of viral RNA can trigger
the innate immune response through pattern recognition receptors
(PRRs).

Abstract

Ribonucleic acid (RNA) plays an essential role in the cellular processes of gene
expression, protein synthesis, and gene regulation. Unlike DNA, which stores genetic
information, RNA serves as the intermediary that translates genetic instructions into
functional proteins and regulates various cellular activities. This report provides a
detailed exploration of the types of RNA and their roles in biological systems. It
discusses messenger RNA (mRNA), transfer RNA (tRNA), ribosomal RNA (rRNA),
and other non-coding RNAs, including microRNA (miRNA) and small interfering
RNA (siRNA), and their involvement in transcription, translation, and gene
regulation. Additionally, the paper addresses RNA's role in catalysis, viral replication,
and immune responses. The versatility of RNA in cellular functions highlights its
importance not only in basic biological processes but also in emerging
biotechnological and medical applications. This report underscores the significant
contribution of RNA to cellular homeostasis, gene expression regulation, and
biotechnology.
Conclusion:

• Summary of RNA Functions

o RNA plays multiple and essential roles in the cell, from carrying genetic
information for protein synthesis to regulating gene expression and
catalyzing biochemical reactions.

• Emerging Research and Future Directions

o The understanding of RNA has expanded beyond protein synthesis to

include its roles in gene regulation, epigenetics, and disease. Emerging
research is focused on RNA therapies, RNA vaccines, and using RNA
for gene editing technologies like CRISPR.

• Final Thoughts

o RNA is central to many cellular processes, and its versatility and

complexity make it an exciting subject of ongoing scientific research. As
we continue to uncover its roles, RNA's potential in medicine and
biotechnology is enormous.

References

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Molecular Biology of the Cell (4th ed.). Garland Science.
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in gene expression. Journal of Molecular Biology, 429(4), 577-588.
3. Bartel, D. P. (2009). MicroRNAs: Target recognition and regulatory functions.
Cell, 136(2), 215-233.
4. Doudna, J. A., & Charpentier, E. (2014). The new frontier of genome
engineering with CRISPR-Cas9. Science, 346(6213), 1258096.
5. Steitz, J. A., & Warren, S. L. (1969). The interaction of RNA and ribosomes in
the synthesis of proteins. Nature, 224(5216), 1010-1016.
6. Fire, A., Xu, S., Montgomery, M. K., Kostas, S. A., & Driver, S. E. (1998).
Potent and specific genetic interference by double-stranded RNA in
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